Which of the following accurately describes the roles of interleulins (ILs) in hemopolesis? Select one: a. Interleukins play diverse roles, including cell differentiation, immune response, and inflammation, and they are produced by various cells, not just leulocytes. b. Identifying over a dozen interleukins, such as ILK-1, ILK-2, and ILK-3, has provided no understanding of their functions with no further discoveries. c. Originally thought to be exclusive to leukocytes, interleukins are now understood to be produced solely by bone marrow cells. d. Interleukins primarily function in cell differentiation, with limited involvement in immune response and inflammation.